**Retro Review: TI-95 Procalc**

This review covers the calculator itself, not any of the optional accessories which includes a thermal printer and cassette interface.

**Quick Facts:**

Model: TI-95 Procalc

Company: Texas Instruments

Type: Scientific, Keystroke Programmable

Years: 1985-1987

Display: 10 digits for numerical answers, 16 alpha-numeric display

Batteries: 4 AAAs

Logic: Algebraic (AOS)

Original Price: $200.00. I paid $60 I bought it on eBay.

Memory:

Registers: 26 alpha registers, up to 900 numeric registers (three digit registers)

Programming Steps: up to 7,200 steps, default set at 1,000 steps.

Storage Memory: up to 8,000 bytes, set to 5,200 bytes by default.

A separate 8K RAM can be added for an additional 8,000 bytes of memory.

**The QWERTY Keyboard and Other Unique Features**

One look at the keyboard and one may mistake the TI-95 Procalc as a BASIC Programming calculator. However, the TI-95 Procalc is a keystroke programmable calculator. We'll talk about the programming later.

The TI-95 Procalc is one of the first calculators to contain function keys, F1 through F5.

In addition to the standard functions including trigonometry, logarithms, roots, powers, factorials, hyperbolic functions, and statistics including linear regression:

The number menu [ NUM ] has functions including integer part (INT), fractional part (FRC), random numbers between 0 and 1 (R#), round the number displayed to fix number settings (RND), sign function (SGN), lowest common multiple (LCM), prime factors (PF), and absolute value (ABS).

The LCM soft key has two functions:

(LCM) : lowest common multiple.

Example: 4 [ x~t ] 6 (LCM) returns LCM = 12.

(LCM) [ x~t ]: greatest common divisor.

Example: 25 [ x~t ] 40 (LCM) [ x~t ] returns 5 (GCD(25, 40) = 5)

(PF) returns the biggest prime factor of an integer. To get additional prime factors, repeat the keystrokes [ x~t ] (PF).

Example: 28

28 [ NUM ] [ --> ] ( PF ) returns f = 2

[ x~t ] ( PF ) returns f = 2

[ x~t ] ( PF ) returns f = 1 (When you reach f = 1, press [ x~t ] to get the last prime factor, 7)

28 = 2 * 2 * 7 = 2^2 * 7

The conversions menu [CONV] contain several types of conversions:

MET (Metric):

(F - C) °F -> °C (left to right), [INV] (F - C) does °C -> °F (right to left)

All of the conversions follow this pattern.

(G - L) gallon and litre

(# - K) pounds (#) and kilograms (kg)

(i - m) inches (i) and millimetres (m)

(f - M) feet and meters

DMS: convert to D.MMSSS from degrees

INV DMS: convert degrees to D.MMSSSS

ANG: convert between Degrees (D), Radians (R), and Grads (G)

P-R:

r [ x~t ] θ [ P-R ] results: y [ x~t ] x (polar to rectangular)

x [ x~t ] y [ INV ] [P-R] results: θ [ x~t ] r (rectangular to polar)

BAS: (Bases)

DEC: convert to base 10 and set the TI-95 Procalc to Decimal Mode

HEX: convert to base 16 and set the TI-95 Procalc to Hexadecimal Mode

OCT: convert to base 8 and set the TI-95 Procalc to Octal Mode

2sC: convert to 2's complement format

UNF: convert to un-formatted display mode

Two things to note:

1. Hexadecimal numbers A-F are accessed with the [ 2nd ] key.

2. There are no conversions to binary integers

The FUNC key has three operations:

QAD: Find the roots, real or complex, of the quadratic equation a*x^2 + b*x + c = 0

CUB: Find the roots of the cubic equation a*x^3 + b*x^2 + c*x + d = 0

SYS: This is not a solver for system of equations. Instead, it allows the user to turn system protection on or off. With system protection off, the user can edit specific bytes of memory. The aim for unprotected system memory mode is to assist the user in assembly programming.

Fun Fact: FIX 9 sets the TI-95 Procalc to floating mode.

One more fun fact: The factorial functions accepts arguments of both integers and integers in the form of n + 1/2. The latter can include negative numbers. You will not see this in any other standard scientific calculator (outside the CAS-enabled factorials).

**Help: But Not What You Expect**

The HELP key does not give help on the specific functions. Instead, the HELP key asks the user "SET NORMAL MODE?". Yes resets the TI-95 to decimal mode, floating standard mode (removes Fix settings), degree mode, and sets memory partition to default (1000 program steps, 125 numeric registers, and 5200 bytes for files). A No asks the user whether to reset any specific mode that is set to default.

**Files, Files, and More Files**

The FILES key is where you would store, load, and delete program and data files. Files have three characters (fixed so the file "A " has A followed by two spaces). FILES is also where you access the 8K RAM or additional RAM cartridges. It's pretty neat how the FILES system works once it is learned.

**The ALPHA Register**

Similar to the HP 41C and HP 42S, the TI-95 Procalc has a 16 character ALPHA register. The ALPHA register is used to display results and prompt messages. Numeric registers call be recalled into the ALPHA register.

Example: 11 is stored in register A. ANSWER = is in the ALPHA register. Pressing (COL) 16, moves the cursor to column 16. (MRG) A places 11 at the 16th space justified right.

ALPHA register: ANSWER = 11.

MRG = recalls the number from the display/last answer.

The ALPHA register can contain lower case letters and ASCII characters simular to the TI-58/59 family.

**Keystroke Programming**

The TI-95 Procalc has algebraic keystroke programming with labels, tests against numeric registers, increase and decrease by 1 (INCR and INV INCR, respectively) functions, define menus (DEF), the use of ALPHA register.

Unique is the YES/NO function. Y/N creates a two function menu (F1: YES, F2: NO) and works like the rest of the test commands.

Y/N

(do if YES is pressed)

(skip to here if NO is pressed)

Labels are two characters which can contain both numbers and letters. Go to and subroutines to labels are use the commands GTL and SBL.

The halt command, HLT, stops program execution. While the break command, BRK temporarily stops the program execution to display the current result and sets F1 to GO.

Storage arithmetic is permitted.

Example program: PRF which automates the prime factors of an integer.

**TI-95 Procalc Program: Prime Factors**

1

STO A

'NUMBER?'

BRK

LBL 00

PF

'FACTOR = '

COL 16

MRG =

BRK

IF= A

GTL 01

x~t

GTL 00

LBL 01

x~t

'FINAL = '

COL 16

MRG =

HLT

(50 steps)

Example: 158

'NUMBER?' 158 (GO)

'FACTOR= 2.' (GO)

'FACTOR= 1.' (GO)

'FINAL= 79.'

158 = 2 * 79

The TI-95 Procalc comes with a har dcase and a gray help card.

**Verdict**

I like this calculator, having a solid set of functions with adjustable programming space. Having the 8K RAM card, which came with the calculator when I bought it, allows me store programs on the card without having to worry about storage space as much.

There are several things I have to get used to: the program steps scroll horizontally instead of vertically, and both the break (BRK) and halt (HLT) operate differently from the modern definition. Thankfully both the operating and programming manuals are still available online through the Datamath website.

The price point is pretty high at $200.00, as the TI-95 Procalc was set as Texas Instruments' high end programmable keystroke programmable.

The Datamath page has an emulator: http://www.datamath.org/Graphing/TI-95.htm

Eddie

Source:

Woerner, Joerg. "Texas Instruments TI-95 PROCALC" Datamath http://www.datamath.org/Graphing/TI-95.htm Last Edited December 5, 2001. Accessed June 22, 2020.

All original content copyright, © 2011-2020. Edward Shore. Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited. This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.